The proposed research seeks to develop a powerful self-administered maintenance program for non-smoking; assess the relative effectiveness of nicotine gum, placebo gum, or no gum in promoting long-term abstinence; compare the relative efficacy of ad lib versus continuous nicotine gum use regimens; assess the effects of a psychological self-help maintenance program; compare the relative effectiveness of different strategies for administering the psychological maintenance program; and provide biochemical validation of subjects' smoking status for two years following cessation. Research designed to improve the service delivery of smoking cessation procedures is important because survey data indicate the most smokers who desire to quit prefer self-administered, minimal-contact treatment formats. However, such self-help procedures need more rigorous assessment and longer-term follow-up. Furthermore, it is likely that both psychological and pharmacological mechanisms contribute to the durability of the smoking habit. Pharmacologic aids such as nicotine gum may be useful in combating the effects of withdrawal. Psychological procedures appear needed to help quitters manage psychological factors that may promote relapse. The integration of pharmacological and innovative psychological strategies within a minimal contact format offers a new challenge for smoking researchers. The research design is a 2 factor, 3x4 fully crossed experiment. The psychological factor has 3 levels: self-selected relapse prevention modules, randomly-selected modules, and survey only. The pharmacologic factor has 4 levels: nicotine gum administered either ad lib or on a continuous schedule, placebo gum, and no gum. l200 persons, able to quit for 48 hours, will be assigned randomly to one of the l2 treatment cells. The relapse prevention modules will be mailed to subjects on a weekly basis for 8 weeks. Subjects will use self-efficacy scales to pinpoint "high-risk" situations and devise plans for coping with these situations. Assignments will be mailed back to the program offices each week. Nicotine and placebo gum will be given for l2 weeks. Mail-ins, financial deposits, and telephone prompts will be used to boost adherence to protocols. We will assess reported smoking, perceived self-efficacy, physical dependency, withdrawal symptoms and side-effects, as well as expired-air carbon monoxide and saliva thiocyanate. Measures will be collected at 0, 2, 6, l2, and 24 months. Power calculations show that we can detect 8-l0% differences in reported abstinence and even smaller effects for continuous variables such as reported cigarettes per day.